1. Field of Invention
This invention generally relates to the field of combustion engine accessories and in particular to a novel constrictor valve for controlling air intake into a cylinder of an engine.
2. Description of the Related Art
The automotive industry has always had the belief that large intake ports on cylinder heads make horsepower at high revolutions per minute (rpm) (above approximately 3000 rpm). However, due to their size, these large ports have air flow that is slow at lower rpm, below 3000 rpm, making them unusable in daily driving on the street, especially when the typical automobile spends most of its time below 3000 rpm. This is due to the fact that when the piston in the engine is moving up and down in the cylinder, a vacuum is created. This vacuum at 800 rpm idle for most automobiles pulls air and fuel from the carburetor or fuel injection system, through the intake port of a cylinder head, down inside the combustion chamber to be ignited to make power to keep the engine continuously working. By varying the size of the intake port, one can change how much fuel and air the engine can take into the combustion chamber. At high rpm and vacuum, the engine is theoretically limited in its power ability by the size of the intake ports. Large ports have large airflow but slow air speed, while small ports have less airflow but faster air speed.
The problem can be illustrated through a simple exercise by taking a certain size straw and sucking a milk shake through it and then comparing the movement of the milkshake with that produced by a larger diameter straw. One will find the suction is less on the larger diameter straw and the milkshake moves slower through the straw. In an analogous fashion, larger ports have a lower flow velocity given the same flow demand.
In more technical terms, an air column of a given mass at a lower velocity has less inertia and potential energy possible, thus negating any ram air effect. The ram air effect is critical for obtaining a complete cylinder filling at low rpm and is just as critical for maximizing volumetric efficiency at high rpm. Accordingly, incomplete cylinder filling at low rpm causes an engine to have poor bottom end power and throttle response. For these reasons, large ports are mainly reserved for racing-type engines only.
The automotive industry logically uses smaller ports for factory cars because smaller ports make a power band more useful to the average motorist on the street. This is due to the faster airflow delivered by smaller ports. Since the speed of the mixture of fuel and air determines how tightly the combustion chamber is packed, the more tightly packed the combustion chamber, the more pressure develops when the mixture is ignited. As a result, the piston is pushed with more force for more power.
To the inventor""s knowledge, there is no dual-purpose cylinder head available. Until now, there has been either large ports for racing or small ports for the street. However, by placing a constrictor valve inside a cylinder head intake port (ideally approximately one-half to three-quarters of an inch the size of the port), one can make a large port speed up airflow. But as the rpm increases a constrictor valve would adjust by a vacuum pulling on it, causing it to open up to a large port size at a specific rpm again. Accordingly, one achieves a low rpm throttle response and high rpm horsepower all in one. Basically, a cylinder head that was believed to work only at high rpm can be used at lower rpm also.
The invention generally relates to a device for increasing airflow speed through an inlet port of an automotive cylinder head. More specifically, the invention relates to a pivot valve for an intake port of a cylinder head that is balanced such that the pivot valve is relatively more open during greater airflows and more closed during lesser airflows.
It is an object of the invention to provide more power capability from virtually any internal combustion engine that uses intake ports such as lawnmowers, gas-powered weed eaters, generators, motorboat engines, etc.
A second object of the invention is to eliminate the need for more costly and less reliable devices which speed airflow such as turbochargers and superchargers.
Another object of the invention is to provide a valve that responds to airflow through an intake port of a cylinder head such that airflow speed is increased at lower rpm""s.
In accordance with these and other objectives, the invention features a valve that is pivotally attached inside the intake of a cylinder head and means for urging the valve to a closed position such as by a counterweight or spring.
Various other purposes and advantages of the invention will become clear from its description in the specification that follows and from the novel features particularly pointed out in the appended claims. Therefore, to the accomplishment of the objectives described above, this invention consists of the features hereinafter illustrated in the drawings, fully described in the detailed description of the preferred embodiments and particularly pointed out in the claims. However, such drawings and description disclose only some of the various ways in which the invention may be practiced.